1. Field of the Invention
The present invention relates to an image processing apparatus, an image output system, an image processing control method and a computer readable information recording medium. In more detail, the present invention relates to an image processing apparatus, an image output system, an image processing control method and a computer readable information recording medium, by which even in a case where color reproduction elements such as an image output method of an image output apparatus, an output medium and/or the like are different, image processing is carried out in such a manner that an image can be output with the required color reproduction.
2. Description of the Related Art
As communication networks have been developed, printing systems such as a “Web to Print” system and so forth have appeared. In the “Web to Print” system, printing request apparatuses such as plural computers and a printing request receiving apparatus of a printing company are connected by a communication network such as the Internet. The printing request receiving apparatus includes plural image forming apparatuses (printer apparatuses, multifunction peripherals and/or the like) of plural image forming methods (offset printing method, electrophotographic printing method, ink-jet printing method and/or the like). In this system, based on image data and printing apparatus designating information for designating the image forming apparatus that prints an image transmitted from the printing request apparatus via the communication network, the designated image forming apparatus prints an image on an output medium such as paper, a film or the like based on the transmitted image data.
In such a printing system, image forming apparatuses of various image forming methods are prepared, a user can designate an image forming apparatus for printing an image from printing data (image data) to transmit as an image forming apparatus that prints the image for the purpose of forming a desired image at a desired cost. However, the designated image forming apparatus may be in a printing unavailable state due to a failure or because it is currently printing a large amount of data. In such a case, the user should again select another image forming apparatus as an image forming apparatus to print an image, and cause it to print the image.
However, when the image forming apparatus that prints an image is thus changed, the color gamut may become different depending on the image forming method, thus the colors of the image obtained through printing may become different, and the desired image may not be obtained.
A color conversion apparatus has been proposed (see Japanese Laid-Open Patent Application No. 2002-252785 (Patent reference No. 1)). This color conversion apparatus converts input color data expressed by any color system into color data with which any color image output apparatus can reproduce the colors. The color conversion apparatus includes a color reproduction range A storage part that stores a color reproduction range A of the color image output apparatus and a color reproduction range B storage part that stores a virtual color reproduction range B that at least includes the color reproduction range A. The color conversion apparatus further includes a first color conversion part that carries out color compression of the input color data referring to the virtual color reproduction range B stored by the color reproduction range B storage part. The color conversion apparatus further includes a second color conversion part that carries out color compression of the color data that has undergone the color compression by the first conversion part referring to the color reproduction range A stored by the color reproduction range A storage part. The color conversion apparatus converts the input color data into color data with which the color output apparatus can reproduce the colors. This art attempts to reproduce colors with the same impression even using different output devices (i.e., image forming apparatuses to carry out printing such as printer apparatuses) for the purpose of carrying out uniform color reproduction using plural image forming apparatuses. For this purpose, a color gamut of a virtual device is defined. The color gamut of a virtual device encompasses color gamuts of plural image forming apparatuses, and also, has the shape closer to output devices than input color spaces such as sRGB, AdobeRGB and so forth (Adobe is a registered trademark). Then, in the thus defined color gamut, typical color data obtained from color compression of input color data is stored. Then, color compression is carried out from the typical color data into a color gamut of an output device so as to reproduce colors with the same impression even using the different output device. Thus, this art attempts to carry out uniform color reproduction even using plural image forming apparatuses.
Further, an image processing method has been proposed (see Japanese Laid-Open Patent Application No. 11-313216 (Patent reference No. 2)). In this method, color reproduction range information of a target output device is input. Color reproduction range information of plural output devices different from the target output device is input. Then, based on the color reproduction range information of the target output device and the color reproduction range information of the plural output devices, an output device is automatically selected from among the plural output device to be used for carrying out a proof of the target output device. This art compares the color gamut of the target output device with the color gamuts of the plural output devices different from the target output device. Then, in a case where an output device has been discovered which is different from the target output device and encompasses the color gamut of the target output device, the discovered output device is automatically selected as an output device for carrying out a proof of the target output device.
However, in the above-described related arts, it is attempted to carry out outputting of an image having impression of the same colors only considering an output device. Thus, consequently it may result in an output image having colors different from desired ones. That is, not only an output device but also an output medium affects colors of an output image. For example, the color gamut may become different depending on a color reproduction element such as whether an output medium is paper or a film; whether the type of paper is coated paper, non-coated paper, glossy paper or the like; whether the thickness of paper is cardboard, plain paper, thin paper or the like; and whether an output medium is a display device, a projector or the like instead of paper or a film. That is, the color gamut of an output image may become different or be in the same range not only due to a difference in an output device but also due to a difference of a color reproduction element such as an output medium. As a result, even when a virtual color gamut or typical colors is/are determined for each image forming method as in the related arts, it may be difficult to make the impression of colors identical at a time of outputting because of a difference in an output medium. Further, in a case of defining a virtual color gamut to encompass the color gamuts of plural output devices, it may be necessary to increase the highest chromaticness of a virtual color gamut for a certain hue, or increase the reproducible lightness range. As a result, the divergence between the actual color gamut of an output device and the virtual color gamut may be increased, and the uniformity of colors among output devices may be lost.
Further, there may a case where printing colors of a target output device are simulated using another output device, or it becomes necessary to use another output device for printing because a target output device has a failure. In such a case, the other output device may not completely encompass the color gamut of the target output device. In such a case, it may not be possible to know how much difference in colors will occur at a time of actually outputting image data, even when a numerical value is shown which indicates the magnitude of the common color gamut part between the target output device and the other output device or the magnitude of the part of the color gamut which is not encompassed by the other output device. Thus, it may be difficult to determine whether it is possible to place an order or give an instruction to continue the printing.